The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. However, these advances have increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed.
A wet etching operation performed on a sacrificial layer (e.g. silicon nitride) is common in a semiconductor manufacturing process. However, for the wet etching operation, insufficient selectivity between the sacrificial layer and its underlying or nearby layers and a loading effect in which an etch rate highly depends on an etched structure result in difficulty in controlling the etch rate.